Traveling-wave valve arrangement

ABSTRACT

For a traveling-wave valve arrangement with a traveling-wave valve and a linearizing circuit arrangement, it is proposed to design the linearizing circuit arrangement and the traveling-wave valve as one constructional unit and, for the thermal protection of the linearizing circuit arrangement in the simultaneous presence of a high permissible temperature of the valve housing, to maintain the circuit arrangement by means of an active cooling element at a nondamaging temperature lower than the one of the wall of the valve or of a common wall. The cooling element is preferably a Peltier element.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of PCT/DE99/01707 filed on Jun. 1,1999.

FIELD OF THE INVENTION

The invention relates to a traveling-wave valve arrangement with atraveling-wave valve and a linearizing circuit arrangement.

THE PRIOR ART

Traveling-wave valves are preferably employed as high-capacityamplifiers in the microwave range, and in particular in satellites. Thepower lost in the course of operation of such amplifier valves isdissipated as heat into the environment. When such valves are employedwith satellites, the heat is dissipated into space through emission,whereby the housing of the valve is typically secured on the inner sideof a heat-conducting wall section of the satellite, and the heat lost isdissipated via the housing of the valve into the wall section andemitted by the wall section. The emitting surface may become smaller asthe temperature of the surface increases with no change in the emissionpower. A permissible minimum temperature of the housing of, for example,100° C. is therefore frequently required for the valves. The highcomponent of power lost by the valve collector is partially emitted viaseparate radiators projecting from the satellite housing.

Traveling-wave valves exhibit a distinct phase response within theoperating frequency band. For the purpose of compensating such a phaseresponse, it is known to transmit the control signals for the valves viaa linearizing circuit arrangement with a complementary phase response.The circuit arrangement is herein briefly referred to as a linearizer.The connection between the signal generator, the linearizer and thesignal input of the valve is typically realized via flexible coaxialconnections. This protects the circuit arrangement against damage by thehigh temperatures of the valve in that it is located with a spacing fromthe valve.

SUMMARY OF THE INVENTION

The present invention is based on the problem of proposing anadvantageous traveling-wave valve arrangement with a traveling-wavevalve and a linearizing circuit arrangement.

The invention results in a traveling-wave valve arrangement that isavailable to the user as a linearized traveling-wave valve without thepreviously required outside wiring while retaining high permissibletemperatures of the housing at the same time. The constructionalcombination reduces the space requirements of the arrangement and avoidsthe expenditure for connections that is associated with circuitarrangements which otherwise have to be integrated in the feed line.Furthermore, the constructional combination of the linearizer with thetraveling-wave valve offers the user substantially simplified handling,and offers the manufacturer the possibility of being able to offerthrough individual adaptation of the linearizing circuit arrangement tothe individual valve a type of valve with guaranteed very goodlinearity. Influences deteriorating the linearity properties as a resultof unfavorable installation measures at the user's facility can beexcluded to a large extent.

An important feature of the arrangement as defined by the invention isthe use of an active cooling element that keeps the linearizing circuitarrangement, herein also briefly referred to as the linearizer, at atemperature lower than that of the wall of the valve. The active coolingelement is characterized in that it dissipates heat from a coldersurface into a warmer surface. Because of the mechanical insensitivityof the simple electrical controls and the long useful life, the activecooling element is preferably a Peltier element.

By employing an active cooling element and due to the power lost in theelement, the power loss occurring in the valve arrangement that has tobe discharged is in fact increased overall. However, the power losscomponent caused by the cooling element is low as compared to the powerloss of the travelingwave valve, on the one hand, and any minor increasethat may occur in the temperature of the housing of the valve due to theadditional loss component is not critical, on the other hand.

The temperature of the linearizer is limited by the cooling element to atemperature not critical for the structural components of thelinearizer, preferably to 60° C. at the most. The cooling element can beemployed as an active element with controllable cooling capacity in atemperature control circuit with a temperature sensor for thetemperature of the linearizer, whereby the controllability of a Peltierelement is again especially advantageous. The linearizing circuitarrangement may be present, for example in the form of a structure on aprinted circuit motherboard with a plurality of components, or fullyintegrated in the form of an individual integrated circuit.

The linearizer is usually arranged in an electromagnetically screenedhousing in order to avoid interference caused by leakage fieldsespecially of the traveling-wave valve. In the arrangement as defined bythe invention, the housing advantageously acts as an additionalradiation barrier and heat insulator against the emission of heat fromthe valve located in the immediate proximity, or from a common housingof the valve arrangement that may enclose also the housing of thelinearizer. By designing the inwardly and/or outwardly facing surfacesof the housing for low radiation emission or radiation absorption powerfor heat radiation, it is possible to further reduce heating of thelinearizer via this path of radiation.

The linearizer is mechanically connected with the wall of the valve orwith the wall of a common housing of the valve arrangement substantiallyonly via the cooling element, so that no or minimal solid-body heattransfer takes place from the wall to the linearizer. In an advantageousembodiment of the invention, the housing of the linearizer is securedwith a surface of the housing on the cooling surface of the coolingelement, which therefore serves as the mechanical carrier that ispreferably secured with its heat-radiating surface on the valve wall oron a common wall. Also, the heat-emitting surface of the cooling elementcan be directly joined with a heat-dissipating surface of an object suchas an outside wall of a satellite.

In another advantageous embodiment of the invention, the cooling elementis arranged, with at least its cooling surface, within the housing ofthe linearizer, and the cooling element is preferably used directly asthe carrier for the linearizing circuit arrangement, in that thelinearizer is mechanically secured on the cooling element, as opposed toan arrangement having a common carrier plate. This establishes goodthermal contact with the linearizing circuit arrangement. Theheat-emitting surface of the cooling element can then be advantageouslycoupled with a surface of the housing of the linearizer, and the surfacecan be thermally coupled with a wall of the valve or with a common wallor with a heat-dissipating surface of the object.

The linearizer is advantageously arranged near the radiation generatingsystem and/or the signal input of the valve and far away from thecollector of the valve, so that stronger radiation of heat into thelinearizer due to the high temperature of the collector, as well as longsignal paths from the linearizer to the signal input are avoided.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in greater detail in the following with thehelp of preferred exemplified embodiments and by reference to thedrawing, in which:

FIG. 1 shows a traveling-wave valve arrangement with a linearizerarranged on the valve housing on the outer side; and

FIG. 2 shows a valve arrangement with a linearizer arranged in a commonhousing.

FIG. 3 shows a control circuit for controlling the current through thecooling element.

DETAIL DESCRIPTION OF THE INVENTION

In the arrangement sketched in FIG. 1, a commonly used traveling-wavevalve LR, which is surrounded by a stable wall, is secured with thesurface of a wall on the heat-dissipating outer wall AF of a satellite.The heat emitted by the traveling-wave valve via its housing surfacethat is in contact with the satellite wall AF, is distributed in theouter wall AF of the satellite through solid-body heat conduction over alarger surface area, and primarily dissipated into outer space throughthe heat radiation R. The traveling-wave valve is in a typical waystructured from a radiation generating system ST, a delay line L, and acollector C, and has a high-frequency signal input E and a signal outputSA through the housing wall W. The interior structure of traveling-wavevalves is known and of no importance to the invention in detail.

A cooling element K in the form of a Peltier element with a coolingsurface KL that is cooler during operation, and with a warmerheat-emitting surface KH, is secured on a part of the surface of thewall W of the traveling-wave valve LR near the radiation generationsystem ST and the signal input SE. The cooling element can be secureddirectly by gluing, using an adhesive with good thermal conductivity, orwith the help of fastening means not shown in detail. The heat-radiatingsurface is in good thermal contact with the wall W of the traveling-wavevalve.

The housing G of a linearizer is fastened on the cooling surface KL ofthe cooling element K, whereby the housing is again fastened with goodthermal contact between a surface of the housing G and the coolingsurface KL, and can be secured via adhesive or with the help offasteners not shown. The actual linearizer is arranged in the interiorof the housing G in the form of a circuit arrangement S present there asa structure on a printed circuit motherboard, or in the form of anindividual integrated circuit. The linearizer is screened by the housingG against electromagnetic radiation, in particular against leakagefields of the traveling-wave valve LR. A high-frequency control signalcan be supplied to the linearizer via an input connection E. Thehigh-frequency input signal, which is provided with a pre-distortingphase response that is complementary with respect to the phase responseof the traveling-wave valve, is supplied to the signal input SE of thevalve with a short length of the line leading from the linearizer to thevalve. Since cooling of the circuit arrangement S by the cooling surfaceKL of the cooling element K is of primary importance, the circuitarrangement S is in good thermal contact with the cooled surface of thehousing G. The housing G effects at the same time screening of thecircuit arrangement S against direct heat radiation into the latter fromthe wall W of the traveling-wave valve, the wall being heated to a hightemperature.

It is assumed that a temperature value of, for example 100° C. ispermissible during operation for the temperature of the wall W of thetraveling-wave valve at a reference point TP. The areas of the wall Wthat are not directly in contact wit the heat-dissipating wall AP of thesatellite, may also reach higher temperatures. The cooling element K,which in particular is a Peltier element, transports heat from thecircuit arrangement S via a surface of the housing G and the coolingsurface KL to the heat-emitting surface KH, which is at a substantiallyhigher temperature, and transfers the heat into the wall w of thetraveling-wave valve. It is assumed that the temperature of the circuitarrangement is limited by the cooling element to maximally 60° C. Via acontrol circuit CC whose components are shown in FIG. 3 and which inparticular comprises temperature sensor TS located on or near thecircuit arrangement S and a controlling device CD for controlling thecurrent through the cooling element K, it in possible to control theelectric power absorbed by the cooling element K for maintaining thecircuit arrangement S at a substantially constant temperature.

The arrangement sketched in FIG. 2 substantially differs from thearrangement according to FIG. 1 in that the linearizer with thecompletely screened housing G is arranged within a common housing of thetraveling-wave valve arrangement, whose wall is again denoted by W. Theinput connection E leading to the linearizing circuit arrangementextends through the common wall W. The connection between the linearizerand the signal input of the traveling-wave valve is realized within thecommon wall W, for example through a hollow conductor section H. Withinthe common wall, the traveling-wave valve and the linearizer areseparated from one another preferably by a separation wall T, whichreduces leakage fields and blocks off direct heat radiation. Thelinearizer is located at the end of the traveling-wave valve structure,the end being disposed in the location of the radiation generatingsystem ST and delay line L.

In the example sketched in FIG. 2, the cooling element K is arrangedwithin the housing G of the linearizer. The circuit arrangement S ispreferably secured with good thermal coupling on the cooling surface KLof the cooling element K serving as the carrier, for example via anadhesive coating with good thermal conductivity. The heat-emittingsurface KH of the cooling element K abuts a surface of the linearizerhousing G, which in turn abuts the inner side of the wall W. Goodthermal coupling is again realized between the heat-emitting surface KHof the cooling element K, the abutting housing section of the linearizerhousing G, the common wall W, and the heat-dissipating wall AF of thesatellite. The considerations stated with respect to FIG. 1 areaccordingly applicable to the operation of the arrangement and inparticular to the operation of the cooling element K.

In addition to the sketched arrangements according to FIGS. 1 and 2,different variations are conceivable that combine details of thearrangements in different ways. In particular, an arrangement with acooling element located within the housing G of the linearizer may besecured from the outside on the wall of a traveling-wave valve, or thecooling element may be arranged between an inside surface of a commonwall W and a linearizer housing G located within the common wall. Thepositions for the arrangement of the linearizer housing G and thecooling element K in the embodiments described above have to be viewedas being only exemplified positions. The sketched exemplifiedembodiments are primarily designed under the aspect of descriptivenessof the figures. In particular, the linearizer housing can be securedalso on a side surface or end surface of the wall W.

The invention is not limited to the preferred exemplified embodimentsdescribed above, but can be modified in some ways within the frameworkof the skills of the expert. In particular, a Peltier element mayoverall serve for stabilizing the temperature versus higher and lowertemperatures and thus make it possible to constructionally combine in avalve arrangement temperature-sensitive components with other componentswith different permissible operating temperatures.

What is claimed is:
 1. A traveling-wave valve arrangement comprising atraveling-wave valve and a linearizing circuit arrangement forcompensating a phase response of said traveling-wave valve, wherein saidlinearizing circuit arrangement and said traveling-wave valve compriseone constructional unit and said linearizing circuit arrangement ismaintained at a lower temperature than a wall of said traveling-wavevalve by an active cooling element.
 2. The arrangement according toclaim 1, wherein said linearizing circuit arrangement is disposed in anelectromagnetically screened housing, wherein said electromagneticallyscreened housing has an outer surface and an interior.
 3. Thearrangement according to claim 2, wherein said outer surface of saidelectromagnetically screened housing is cooled by said active coolingelement.
 4. The arrangement according to claim 2, wherein said activecooling element is disposed within the interior of saidelectromagnetically screened housing.
 5. The arrangement according toclaim 1, wherein said linearizing circuit arrangement is disposedproximate to a radiation-generating system of said traveling-wave valve.6. The arrangement according to claim 1, wherein said active coolingelement dissipates heat emitted by said linearizing circuit arrangementinto said wall of said traveling-wave valve, or into a common wall ofsaid traveling-wave valve and said linearizer when said linearizer andsaid traveling-wave valve are arranged within a common housing.
 7. Thearrangement according to claim 1, wherein the cooling capacity of saidactive cooling element can be controlled.
 8. The arrangement accordingto claim 1, wherein the temperature of said linearizing circuitarrangement is maintained below 60° C. by said active cooling element.9. The arrangement according to claim 1, wherein said active coolingelement is a Peltier element.